This disclosure is directed to a battery testing system. It is a testing system which is intended to be used with batteries of all types, sizes and shapes. Examples of batteries that can be tested are the high volume, low cost batteries having a nominal cell voltage of 1.5 volt DC and which are provided in cylindrical shells conforming with industry standards for batteries such as AA, AAA, B, C and D. While there are many other sizes, these are typical of the elongate cylindrical battery which has a positive terminal at the upper end and a negative terminal at the lower end. That is a first or representative size. In addition to that, there are circular batteries shaped more as a button. The positive terminal is at the upper end and the negative terminal is at the side of the button. While cylindrical, the diameter is usually two or three times greater than the thickness. Testing of cylindrical and button cells will be the primary examples, but that is not intended to exclude testing of rectangular batteries which have two terminals on the top end. These contrast with the AA cells or the button type cells (type PX625 cells) in that they may readily include two or more cells in a single housing which are connected so that they provide a desired terminal voltage which is higher than 1.5 volts. For instance, a 12 volt cell is comprised of eight serially connected individual cells which are assembled in a single structure in a single housing having one pair of terminals. Such multi-cell batteries providing higher voltage than 1.5 volts will be denoted hereafter as HVB (meaning multi-cell or high voltage batteries). It is assumed that the A, B, C and D cells can be exemplified by a particular dimension such as the AA cell, and that will be denoted hereinafter as the AAB meaning a single voltage cell of cylindrical construction conforming with the AA standard. Button shaped batteries will be known hereinafter as BB representing button batteries.
Other types of batteries can also be tested and that includes NiCd batteries, lithium type batteries, and others which happen to be rechargeable. Accordingly, the test equipment and several of the test procedures set forth below apply to batteries which are capable of multiple charges, i.e., they can be recharged. It also applies to those which cannot, namely, chemical cells which undergo an irreversible chemical conversion and are no longer chargeable.
It is not uncommon to manufacture several thousand AAB per hour. Indeed, they typically must be manufactured in large volume to be able to profitably make such batteries. Further, it is not uncommon to make a large number of batteries which pass all requirements for the particular quality control standards applied to a particular battery. Occasionally, something will go wrong with the manufacturing process. For instance, the chemicals which make up the AAB may be off standard. The assembly may be erratic and sub standard batteries are then made thereby. It is not uncommon for this to happen thereby causing the manufacture of a large number of defective batteries. When that occurs, the defective batteries need to be screened and not shipped. While the manufacturer can tolerate shipment of an occasional battery which is defective, either in terminal voltage or life, it is highly desirable that the manufacturing process be controlled with sufficient quality control (QC) that specified high QC standards are met. This involves substantial testing. Whether random individual units are tested or the entire production run, routine QC testing is helpful. In one aspect of the present disclosure, testing is enabled for all levels of QC including random or sampled selection at one extreme to testing of the entire production run at the other extreme. The present apparatus is a system which enables such testing. It will be described in the context of making perhaps 100,000 or more AAB during a production run.